The present invention relates to power adapters and connector arrangements for adapting power supplies to connectors found in different countries.
Portable electronic devices commonly rely on AC adapters for operating the devices from the AC power mains, and charging batteries. Manufacturers of these devices, as well as their users, face problems in their use in different countries. The electronics arts have provided power supplies that can readily adapt to the wide range of operating voltages found around the world. But, this variety of operating voltages is a simple problem compared to the many different physical designs for power connectors that supply mains voltages. These power connectors vary from country to country. A number of solutions have evolved to this problem. One solution is to sell a different power adapter, with the proper connector configuration, for each country. This is a burden for manufacturer and user alike, and unsatisfactory to both. A second solution is to build a single power adapter having a connector for applying the mains voltage, and supplying adapter connectors tailored to the mains connectors required for each country. This is the approach used in the power supply for the Apple.RTM. Computer, Inc. Duo.RTM. series of portable computers (trademarks of Apple Computer, Inc.); a industry standard IEC receptacle is built into the power adapter, and separate adapters each having a corresponding IEC plug, and the required mains connector for that particular locale are provided. This reduces the manufacturing burden; only one power supply need be built, and one simple plug adapter for each locale. The user need only carry one supply, and a set of adapters for those countries needed. The user must always remember, however, to carry one adapter; if they remember to take the supply, but not the mains adapter, the supply cannot be used. A third solution is to build the supply with a permanent connector for one locale, and either supply adapters, or leave the problem to the ingenuity of the user. This is the approach used by the Apple Computer, Inc. PowerBook series of power supplies, such as the M5140 supply provided with the PowerBook 140 series of computers. This supply is permanently fitted with two metal prongs suitable for use in mains outlets commonly found in North America and Japan. Slip-on adapters, commonly found in convenience stores and at airport stores, adapt the standard North American prongs to the local mains standard. This solution also has a number of problems. First, the fixed metal prongs are a nuisance for the user in packing the device for transport. The prongs must be covered, or protected in some way so that they do not become bent during transit, and also so that the prongs do not damage other articles during transit. Of greater importance is that the use of simple slip-on adapters may not meet the safety certification requirements of some countries. What is needed is a simple scheme for adapting such devices to the varying connector standards of the world, in a manner that is economical to the manufacturer, convenient to the user, and safe.